Vaccination of dogs in an African city interrupts rabies transmission and reduces human exposure

20 December 2017 Vol 9, Issue 421ReportVaccination of dogs in an African city interrupts rabies transmission and reduces human exposure
By Jakob Zinsstag, Monique Lechenne, Mirjam Laager, Rolande Mindekem, Service Naïssengar, Assandi Oussiguéré, Kebkiba Bidjeh, Germain Rives, Julie Tessier, Seraphin Madjaninan, Mahamat Ouagal, Daugla D. Moto, Idriss O. Alfaroukh, Yvonne Muthiani, Abdallah Traoré, Jan Hattendorf, Anthony Lepelletier, Lauriane Kergoat, Hervé Bourhy, Laurent Dacheux, Tanja Stadler, Nakul Chitnis
Science Translational Medicine20 Dec 2017 Restricted AccessA citywide dog vaccination effort in Chad reduced the local spread of rabies from dogs to humans.Abstract
Despite the existence of effective rabies vaccines for dogs, dog-transmitted human rabies persists and has reemerged in Africa. Two consecutive dog vaccination campaigns took place in Chad in 2012 and 2013 (coverage of 71% in both years) in the capital city of N’Djaména, as previously published. We developed a deterministic model of dog-human rabies transmission fitted to weekly incidence data of rabid dogs and exposed human cases in N’Djaména. Our analysis showed that the effective reproductive number, that is, the number of new dogs infected by a rabid dog, fell to below one through November 2014. The modeled incidence of human rabies exposure fell to less than one person per million people per year. A phylodynamic estimation of the effective reproductive number from 29 canine rabies virus genetic sequences of the viral N-protein confirmed the results of the deterministic transmission model, implying that rabies transmission between dogs was interrupted for 9 months. However, new dog rabies cases appeared earlier than the transmission and phylodynamic models predicted. This may have been due to the continuous movement of rabies-exposed dogs into N’Djaména from outside the city. Our results show that canine rabies transmission to humans can be interrupted in an African city with currently available dog rabies vaccines, provided that the vaccination area includes larger adjacent regions, and local communities are informed and engaged.